Cut-off controlling mechanism for and method of operating locomotives



y 19, 1932- E. s. PEARCE ET AL 1,358,024 CUT-OFF CONTROLLING MECHANISM FOR AND METHOD OF OPERATING LOCOMOTIVES Filed May 5, 1925 5 Sheets-Sheet l VENTORS gamgx F d m ikwoRNEYs July 19, 1932.

E. S. PEARCE ET AL CUT-OFF CONTROLLING MECHANISM FOR AND METHOD OF OPERATING LOCOMOTIVES Filed y 1,925

5 Sheets-Sheet 2 IN N TORS A TTORNEYS July 19, 1932. '55. PEARCE ET AL CUT-OFF CONTROLLING MECHANISM FOR AND METHOD OF OPERATING LOCOMOTIVES Filed May 5, 1925 5 Sheets-Sheet 3 NVENTORS QJMQF/ f 21/ ATTRNEY July 19, 1932.

E. S. PEARCE ET AL CUT-OFF CONTROLLING MECHANISM FOR AND METHOD OF OPERATING LOCOMOTIVES Filed May 5, 1925 in m mu V A 45in mun III 5 Sheets-Sheet 4.

INV NTORS 6 g ,2 a ATTORNEB July 19, 1932- E. s. PEARCE ET AL CUT-OFF CONTROLLING MECHANISM FOR AND METHOD OF OPERATING LOCOMOTIVES Filed May 5, 1925 5 Sheets-Sheet 5 In n.

INVENTORS GOA ww Patented July 19, 1932 warren STATES PATENT reins EDW'lN S. PEARCE, RAYMOND W. BETTER-ER, AND EDMOND C. KARIBO, OF INDIAN- APOLIS, INDIANA CUT-OFF CONTROLLING MECHANISM FOR AND METHOD OF OPERATING LOCOMOTIVES Application filed May 5,

This invention relates to cut-off controlling mechanism for locomotives and involves improvements on the disclosures in our copending applications No. 319,062, filed August 22nd, 1919 and No. 629,565, filed April 3rd, 1923 the former of which has sincehecome Patent No. 1,595,571 on August 10, 1926, and the latter of which has since hecome Patent No. 1,735,087 on November 12, 1929.

In the said applications we have shown how the cut-off of the locomotive valves can be automatically adjusted to maintain a substantially constant back pressure and that such back pressure can itself be used to control the apparatus. Furthermore, we have there shown that by maintaining a substantially constant back pressure it is possible to develop maximum power at all times. This back pressure may vary in difi erent locomotives but once determined and then maintained it is possible to get the greatest, eficiency from a given locomotive throughout its entire range of speeds.

The apparatus disclosed in said applications was designed to operate the locomotive to capacity at all times. There are many occasions, however, when capacity operation is not required nor desirable. Therefore, if equipped as above specified the train will be operated faster than conditions permit, and with the apparatus of our former applications the engineer had to keep the throttle closed down which, due to the specific construction involved, acted to disable or throw out the automatic cut-0E control thereby necessitating hand regulation of the cut-off.

Nevertheless, automatic regulation of the cut-ofi under the control of the back pressure is just as advantageous when less than maximum capacity is desired from the locomotive as it is when maximum capacity is wanted.

It is, therefore, the primary object of the present invention to provide an automatic,

1925. Serial No. 28,103.

back-pressure controlled cut-ofi' adjusting ratus, however, which are fully disclosed in said case are not treated herein as it is not essential to do so in order to give a complete disclosure of the present improvements.

In the accompanying drawingsFig. 1 is a diagrammatic side elevation of a locomotive with the principal parts of and proper connections for our invention illustrated thereon; Figs. 2, 3 and 4 indicate in more or less diagrammatic form the details, the manner of operation and the relation of the parts of one of our controlling systems with the specifie improvements of the present case added thereto but with certain other parts omitted so as to reduce as much as possible the following specification, such other parts being fully disclosed in our application No. 629,565 Fig. 5 is a side elevation partially in section illustrating certain parts of the apparatus and taken on the line 55 of Fig. 6; Fig. 6 is a vertical cross section through some of the parts of our apparatus; and Fig. 7' is a longitudinalvertical section through a power reverse gear which is particularly adapted for use with our invention. Figs. 3 and l, if placed side 'by'side with Fig. 3 on the right, will eXactl align and form one large diagrammatic View of the device. This has been indicated by the heavy dot and dash line at the left of Fig. 3 and at the right of Fig. {L

Referring to the drawings and first to Fig.

1 it will be seen that the locomotive 1 is equipped with a power reverse gear 2 which is subject to the manual control in the usual way of the reverse lever 3 thru the medium of the reach rod 4 and combination lever 19.

' In a manner well understood in this art the power reverse gear is adapted to be connected to the valve 8a by means of the reverse gear reach rod 6, lift shaft arm 7, radius rod hanger 7a, radius rod 76, links 70, lap and lead lever 7d, and valve stem 8?). Motion is imparted to the valve Saalso in a manner well known to the art by means of the eccentric crank 80, eccentric rod 861 and the union link 8e,'the latter being connected between the cross head 8; and the lower end of the lag and lead lever 7d. The locomotive is driven, of course, through the medium of the usual piston 10a, piston rod 10?), cross head 8;, mainrod 100, crank pin 10d, and side rod 100. I Live steam is admitted to the valve chests 8 through the usual supply pipes 9. Unly one of each of these members as well as of the cylinders 10 and valve gear mechanisms above described are shown but it vill be understood of course that there are two, one on each side of the locomotive. Air from the main reservoir 11 is supplied to the cu tomary valve chest 12 through 13 and 1 1 and the operation of the reverse gear which we prefer to use may be b iefly described as follows. (See Fig. 7 and for a full description reference may behad to our copending application, Serial No. 570,182, (issued on March 18, 1930 as Patent No. 1,751,-

277) in which certain novel features of the reverse gear are specifically claimed.)

The air from the pipe 14: enters the chamber 12a in which it is normally trapped, except when movement of the piston 2a is taking place. Should it be desired to set the locomotive valves 80; for forward motion, the reverse lever (illustrated in its neutral position in Fig. 7) is moved to the right. This causes the rod 4 to be drawn toward the left and with it the upper end of'the lever 19, the latter fulcruming during this operation upon the pivot 19a at its lower end. The rod 19?) extends from the pivot 19a to the pivot 190 on the piston extension 212. This movement of the lever 19 rocks the arm 19d on its shaft 196, the arm being rigid with the shaft, and being pivoted at 199 to the lever 19. The valve operating extensions 1% and 120 on the shaft are also moved, t 1e former downwardly to close the exhaust valve 12d and open the inlet valve 126, and the latter upwardly to open the exhaust valve 12f. Air will then flow from chamber 12a into chamber 12g, past the check valve 12h, out through the pipe 122' and into the chamber 127' at the left of the piston 2a, thus forcing the piston 2a to the right. At the same time exhaust from the chamber 12% at the right of the piston will take place through pipe 1% and past valve 12; to the exhaust chamber 12m. 7

The foregoing action will be continued as long as the reverse lever 3 is being moved forwardly, but just as soon as this is stopped, the motion of the piston 2a, acting through its extension 26, rod 19?), and lever 19. will return the valve operating extensions 12?) and 12d to their neutral or horizontal position and the locomotive valves 8a will be held in the position of adjustment desired. It is to be understood, of course, that the rod 6 is pivoted as at 6a to the piston 2a and that motion thereof is transmitted to the lift shaft arm 7 in the usual manner.

l/Vhen the reverse lever 3 is brought back or moved into the opposite or left hand corner, just the reverse of the foregoing operations are effected, viz., the rod 41 moves forwardly or to the right, the lever 19 swings to the right and with it the arm 19d, and the extensions 12?) and 120 move upwardly and downwardly respectively. Valve 12a is thereby closed, valve 120 opened, and valve 12;? opened. Air passes into chamber 12g, past check valve 129" and out through pipe 1% into the chamber 1270 at the right of piston 2a. The piston 2a then moves to the left and the chamber 12j is exhausted through pipe12'z', valve 12;? and exhaust chamber 128.

t will be understood, of course, that when the piston 2a moves, the lower end of the lever 19, it fu'lcrums at it-s upper end where the pivot 19 f connects it to the rod 20 and through the rod 20 to the reach rode. (This is the well known mode of operation of the floating lever 19. Furthermore, it should be noted that when our improved automatic control of the valves 8a is functioning, the hand control through the reverse lever 3 is made inoperative, and such automatic control takes place through the lever 20, all as will further appear.

When the locomotive is in operation back pressure from the exhaust passages of the valve chests 8 is delivered to the gauge 15 through pipe 16 which divides as shown at the forward end of the locomotive so that a branch enters ateach end of the valve chest 8. It will be understood of course that the connection to one valve chest only is shown but there is a similar connection to the valve chest on the other side of the locomotive. Back pressure is also introduced into what we have termed our controller A by means of a connecting pipe 17. r

The controller A already referred to contains themost important parts of our apparatus and of the present invention all. of which will be described more in detail as its various functions are considered. Suthceit to say at this time that air is supplied to this controller from the main reservoir 11 through the pipe 18 and that the controller through the medium of the air so supplied and under the regulation of the back pressure introduced through the pipe 17 automatically actuates the valve of the power reverse gear to adjust the cut-off. The controller is coupled to the valve operating lever 19 of the power reverse gear (see Fig. 4) by means of the controller reach rod 20.

The air pressure in passing from the reservoir 11 to the controlle A is conducted through what we term the primary control valve D the purpose and function of which will be more fully described hereinafter although at the present time it'is desired-to point out that, after passing through. this pri mary control valve, the air can reach the gauge 15 and also the reverse lever locking cylinder E depending upon the conditions obtaining as will be hereinafter described. The locking cylinder E will also be more fully described at the proper time although it can here be stated that this cylinder locks the quadrant 21 in a stationary position whenever the power reverse gear is manually controlled but permits free rotation thereof whenever the reverse is eutonidically controlled by our improved appa tus. T pressure is conducted to the gang branch of the pipe 18 and to the lo dig c linder E through the pipe 22. hen an: reaches the gauge through the pipe 18 it throws the indicator to auto which means that the locomotive is under automatic control but when the air is exhausted from pipe 18 as will be described later the indicator will show hand which means, of course, that the locomotive is under hand control. (See Fig. 2)

Live steam pressure from the dry pipe of the locomotive is conducted through the pipe 23 to the primary control valve D. There is a globe valve 24 in the pipe 23 which is for the purpose of shutting off completely the supply of live steam should repair, adjustment or replacement become necessary.

In the practice of our invention we desire to maintain a substantially constant back pressure and to utilize any tendency that there may be to increase such back pressure for the purpose of shortening the cut-off and any tendency that there may be to decrease.

such pressure for the purpose of lengthening the cut-off. It is also our intention to do this automatically and with equal facility in either forward or back motion of the locomotive. The means we have employed for accomplishing these ends will now be described in detail beginning on the supposition that the locomotive is standing still and that the engineman desires to start it in a forward direction. lVhen the locomotive is standing still the reverse lever will assume the position indicated in Fig. 1 which is the neutral or central position. When it is desired to go forward the reverse lever will be moved into the forward corner which is the position indicated in Fig. 4 but when it is desired to go backward the reverse lever will be moved to just the opposite corner which position has not been illustrated because it involves simply the reverse of everything that will be described in connection with forward motion. 1 f

Turning particularly to Figs. 2, 3 and 4 and with Fig. 4 arranged to the left of Fig. 3 as indicated in the beginning of this specification itwill be seen that after the reverse lever 3 is moved into the forward corner the reach rod 4 will be drawn backwardly and also the reverse gear-valve operating lever 19. This places the power reverse gear in the proper position to give the longest cut- 1 off possible in forward motion'in a manner which is well understood in this art and is therefore not described in detail nor illustrated. At thesame time the controller reach rod is drawn to the left and with it the operating rod 25 of the controller A.

'The rod 25 is slidably mounted in suitable guides 26. This motion of the rod 25 draws the pin or lug 27. which is fixedly secured to the rod, to theleft also. The pin is surrounded with a roller 28 which rides in a V-shaped slot 29 in the vertically movable cross head 30, the latter'being mounted in guiding standards 31. It will readily be seen that this action will move the crosshead from its upper position illustrated inFig. 5 to its lower position indicated in Fig. 4.

The upper portion of the cross head 30 is provided with a horizontally disposed slot 32 adapted to embrace the roller 33 on the' pin 34 which latter projects into the slot from what we have called our friction wheel 35. The friction wheel 35 is rigidly secured to the ratchet wheel 36 so that motion in one will cause motion in the other.

This initial movement of the reverse lever also brings stop member 37 against pawl 38 thereby moving plunger 39 against the expanding pressure of spring 40 to close valve 41 and open valve 42 for a purpose which will appear hereinafter. v

It is desired to call attention to the fact that the pin 27 with its roller 28 moves from thecenter or lowermost portion of the V- shaped slot 29 to the left hand point of the V. If the reverse lever had been moved in the opposite direction or into the rear corner for backward movement of the locomotive the pin with its roller 28 would have moved from the lower portion-of the V to the upper point of the right hand side thereof. In either case however the motion of the cross head 30 would be exactly the same, namely downwardly in its guiding standards 31. Motion of the friction wheel 35 and of the ratchet '7 wheel 36 would also have been the same as already described. It will also be observed that during initial downward movement of the cross head the downward movement of the pin 33 with its roller 34 would be conteeth 58 on the circular quadrant 21.

siderably less thanduring final movement of the cross head. In other words it is possible to produce a gradually increasing degree of movement in these parts or a gradually decreasing amount of movement When the motion is in the reverse direction as will appear somewhat'later. 7

After the reverse lever has been moved to the forward corner the neXt step in the operation of the locomotive is to open the throttle valve to admit steam pressure through the pipes 9 to the valve chests 8. From there in the manner well known in this art it passes through the cylinders 10 and reciprocates the piston rods to drive the wheels of the locomotive. The throttle valve is not, illustrated nor are other parts ust mentioned for the reason that they do not form a part of the present invention and would simply complicate the drawings. After the throttle valve has been opened live steam pressure, as already specified, is conducted to the primary control valve D through the pipe 23 passing on its way thereto through the globe valve 24.

The first action of the steam on entering the chamber 50in the primary control valve D is to force the piston 51 and slide valve 52 to the right in order to establish communication through the interior of the valve between pipes 13 and 18 thereby permitting air pressure to reach the gauge 15 and also the controller A. The controller is then ready to perform the functions which will now be described and the gauge will indicate that the locomotive is under automatic control. At th same time that this takes place pressure is released from the quadrant locking device through the pipe 22, D-cavity 53 of the slide valve 52 and exhaust port 5 f.

At this point it should be noted that when the locomotive is standing still and the reverse lever is in the position indicated in Fig. 1 air pressure is admitted through the pipe 22 to the operating piston 55 in the reverse lever locking cylinder. This piston is then forced upwardly against the pressure of spring 56 to move the teeth 57 into engagement with the (These parts are clearly illustrated in Fig. 4: althrough the reverse lever would be in the position indicated in 1.) When this lock is set the reverse lever can be moved manually in the usual manner but when the automatic control is functioning this look is released so that the controller reach rod 20 may be free to move the reverse lever reach rod 1 and thereby the reverse lever 3 to the position corresponding to the cut-off obtaining. This portion of the apparatus is provided so that when the locomotive is standing still or when it is desired to adjust the cut-off manually the engineer may move the reverse lever 3 in the customary manner. Under such manual operation the rotatable quadrant 21 is firmly'held in a fixed position by engagement of the teeth 57- With the teeth 58. But just as soon as automatic control of the cut-off begins the teeth 57 are disengaged fromthe forms a number of functions. In the firstv place it enters the friction brake cylinder 60 and forces piston 61 against the pressure of spring 62 upwardly thereby bringing friction brake 53 into contact with friction wheel 35. The wheel 35 and the parts attached thereto and associated therewith are therefore held in a certain fixed position for the time bein The air pressure also and at the same tim flows through passages 64: and 65 into the chamber 66 from which chamber it reaches the chamber 67 through port 68 in slide valve 69, small connecting passage 70, circular passage 71 in the outside of the bushing 72 and passage 73.

Piston 7 is thereupon moved to the left and with it slide valve 75 which we have termed the cylinder supply valve, which establishes communication between passages 76 and 77.

Furthermore air pressure is conducted from the passage 6a into the chamber 7 8 between the two ends of the piston 79. And from the chamber 7 8 pressure can reach the chamber 80 at the left of piston 79 and also chamber 81 at the right of piston 79 through the medium of passages 82 and 83 respectively. In each passage 82 and 83 there is placed a needle valve 8ft- Escape of air from chamber 80 is prevented by means of the slide valve 85 in one direction and valve 86 in the other direction. The air in chamber 81 reaches passage 87 and chamber 88 in what we have termed the cutoff shortening side of the distributing slide valve 85. From chamber 88 pressure flows through the small passage 89 into the chamber 90 below the diaphragm 91. The-area below the diaphragm 91 being larger than the area exposed to the pressure above the diaphragm, the diaphragm will consequently move upwardly as indicated in Fig. 3 and cause member 92 to move ti htly against its seat and prevent movement of the air pres sure out through the exhaust ports 93.

Still further, air from chamber 59 will pass to chamber'Sl-l at the upper end of operating piston 95through ports 64 and 96, holding said piston in downward position at all times when air is not present in chamber 120. Air also .passes from chamber 59 through ports 64 and 146 to cavity to the right of valve 4C2,

passing further as described in a later tion of this specification.

The description so far given might be summed up briefly as follows: The reverse lever has been moved to the forward corner for forward movement of the locomotive, the locomotive throttle has been opened and the pressure of the live steam entering the locomotive valve chests has been employed to admit fluid pressure to the apparatus, preterably air here described. This fluid pres sure has unlocked the circular quadrant, h as applied the friction brake to the friction wheel, has moved the operating piston 95 to its lowermost position, has moved the cylinder supply valve 7 5 to the proper position for admitting fluid to the opposite and larger end of the operating piston (as will appear shortly) and finally has conditioned the distributing valve so that there will be a shortening of the cut-off as soon as the back pressure rises to the predetermined value as the locomotive gets under way. It will be understood of course that in starting a locomotive trom a dead stop the first movement of the valve mechanism must be in the direction of shortening the cut-01f since in starting the longest cut-off is customarily used. (If locomotive is started in a shorter cutoil, it will immediately begin to adjust to ward a longer one upon the opening of the throttle.)

As the locomotive picks up speed the back pressure will radually rise until it reaches a certain predetermined value. This value may vary with difierent classes of locomotives and we have made our device adjustable so that by a little experiment the proper degree of back pressure consistent with greatest eliiciency can be readily determined.

The back pressure is conducted to the controller A through the pipe 17 as already described. It is here delivered to the cham-. her 105 in what constitutes the novel portion of this disclosure which we have termed the duplex pressure regulator G. The bellows diaphragm 106 is thereby subjected to the value of the back pressure and compression or expansion of this bellows diaphragm takes place under the influence of spring 107 against which it works. The pressure of spring 107 can be adjusted either to what we call a maximum capacity setting or to a less than maximum capacity setting. Initial por- . compression of the spring is to less than maximum and is made by the screw plug 108 acting on the piston 1087) in the cylinder 108a. The maximum capacity setting is regulated by the distance the piston 1087) can travel. in compressing the spring 107 before it is stopped by the stop collar 1080 which is threaded into the body casting G1 and held in a fixed position by the lock nut 1081).

The less than maximum capacity setting always leaves a space between the enlarged portion of the piston 108b and, the stop collar 1080. This position is not the one illustrated in the drawings but it will be readily understood from this description. The maximum capacity setting is made by admitting air pressure to the chamber 108a. This forces the piston against the stop collar 1080. If the engineer desires the maximum capacity setting he turns the valve 108E (Fig. 2) so as to permit air pressure from pipe 18 to reach the chamber 1080: through the pipe 1081'.

The bellows diaphragm 106 carries a stem 108G and the piston 1086 a corresponding plunger 10811 which bear on opposite sides of the downwardly projecting arm 109 of a rocking member pivoted at 110 which is provided with two outwardly extending arms 111 and 112. Arm 112 actuates the cut-off shortening side of the distributing valve 85 and arm 111 actuates the cut-ofi lengthening side of the distributing valve. As arm 109 moves to the right arm 112 moves upwardly thereby opening valve 113. This immediately and suddenly lowers the pressure within the chamber thereby causing the member 92 to leave its seat and open passage 87 and chamber 81 to the atmosphere through the ports 93. This exhaust of pressure from the chamber 81 decreases the pressure therein to a point below that in the chamber 80 at the opposite end of the piston 79 and consequently the piston 7 9 will move to the right carry-, ing with itthe slide valve 85.

The first port to be uncovered to the pressure of they fluid in the chamber 78 is the one numbered 114 which communicates with the chamber 80 and this is simply for the purpose of supplying a continued pressure to the chamber 80 in order to ensure a rompt and vigorous motion of the piston 9 and valve 85. r

The next port to be uncovered by the slide valve 85 in its motion toward the right is the one which communicates with passage 76, bridge 117 closing exhaust port 115 and bridge 118 closing the right-hand branch 76a of passage 76 and passage 119 to exhaust. (It should be noted that passage 7 6 can communicate with the chamber 78 at two diflerent places and when the inlet at theleft of valve 85 is opened it is desired that the port 76a at the right be closed to exhaust.) Pres-' sure in passage 76 communicates with passage 77 as already described and admits pressure to the underface of operating piston which it will be noted upon examining Fig.

3 is considerably larger than the upper face- The operating piston 95 will then move upwardly since the pressure in chamber 120 applies'itself to a greater area than the pressure in chamber 94.

In moving upwardly the operating piston 95 carries with it the projecting lug orpin 121 which is connected to what we call the operating spider 122 which isfmouhted for sliding movement up and down in the guides 123. The spider is provided with two outstanding arms 124; and 125 each of which carries a ratchet, the one on the right being number 126 and the one on the left being number 127. The ratchets are spring held to engage the teeth in the ratchet wheel 36 but only one ratchet at a time can engage these teeth on account of the rocking guard 128 which also has a right arm 129 and a left arm 130. To the upwardly projecting portion of this guard 128 there is fastened areach rod 131 connected by the piston rod 132 to the piston 133 normally held in its extreme right-hand position by means of the spring 13%. By this means the guard 128 is rocked slightly to the right in order to lower the right-hand arm 129 and raise the left-hand arm 130. The ends of the-arms are each provided with a substantially vertical face 135 and with a shorter diagonal face 136 immediately thereabove. The incline of the face 136 is toward the center line of the guard. As the spider 122 moves upwardly with the guard in the position shown in Fig. 4 ratchet 126 will move inwardly along the face 136 until its point engages the ratchet wheel 36. At the same time the ratchet 127 simply rides up on the vertical or substantially vertical face 135 so that its point does not come in contact with the wheel 36. The ratchet wheel 36 is then turned counterclockwise for a distance corresponding to the stroke of the operating spider 122. The maximum distance that the ratchet can be turned would correspond to the complete stroke of the spider 122 but this distance can be lessened by altering the position ofthe member 128 with its guard arms 129 and 130. In order to accomplish this we provide the adjusting sleeve 133a threaded into one end of the cylinder 133?) in which the piston 133 reciprocates and also the set screw 1330 at the other end of the cylinder. It is obvious that by reducing the travel .of this piston the ends 129 and 130 of guard 128 will not travel to their lowest positions and, therefore, the ratchets 126 and 127 will not engage the ratchet wheel 36 for such a great distance.

This moves pin 34: upwardly and with it the cross head 30 and since the cross head can move only in a vertical direction the rod 25 and'the connecting rod 20 are pulledto the right since the pin 27 with its roller 28 must .follow the inclined groove of the V slot 29. Valve operating lever 19 is moved to the right to actuate the valve in the valve chest 12 of the power reverse gear in such manner as to shorten the cut-off.

During the upward movement of the operating piston 95 the pin 137 which it carries comes in contact with the slide valve 69 in the chamber 66 and moves it upwardly also.

When the stroke of the piston 95 is com-' pleted the pressure in the chamber 67 is exhausted to the atmosphere through the pas sage 73, connecting passage 70, channel 71, cavity 139 and passage 14:0. The pressure on the left of piston 74 thereupon moves said piston to the right and closes off communicationbetween the passages 76 and 7 7 and at the same time exhausts the pressure in the chamber 120 at the lower end of the operating piston 95, said exhaust taking place through the passage 77 cavity l ll'in the slide valve 75, port 15 1, 1 12 and at times port 100 as explained below. The latter port is capable of V functioning only during initial movement of the reverse gear from its full forward stroke because shortly after the cut-0E begins to shorten, pin 101 will enter slot 102 in the right hand end of operating rod of the controller which slot runs diagonally upwards at first and afterwards horizontally. When the pin 101 enters this slot 102 it will readily be seen that the passage through the valve 99 will be closed because it will be have been rotated out of line with passage 98. Adjustment can be made by means of the screw 102a acting to pinch the forked ends 103 against the interior cylindrical portion. The needle valve 104'is for the purpose of adjusting the speed at which the pressure will flow through passage 98 and valve 99. After valve 99 has closed, the entire exhaust of chamber 120 must pass out through port 142 and by adjusting the needle valve 97 the speed or the rapidity of motion of the operating piston 95 can be controlled. If the needle valve is almost shut it will take several seconds for the air in the chamber 120 to exhaust. But

while exhaust can take place through both passages 98 and 1 12 reciprocation of piston 95 will, of course, be quicker.

As long as it is necessary to keep shortening the cut-0H, namely as long as the back pressure tends to mount higher than the certain predetermined pressure desired, this action will continue and the cut-off shortened until such time as the back pressure remains.

constant. During return movementsof the piston 95, it should be noted that the parts inc adjustment as it approaches the lesser position.

It should also be noted that after the first movement of the ratchet wheel 36 counterwhich the device is 1 off will begin with its incidental counterclockwise the lug 37 moves away from the pawl 38 and thereby permits valve 42 to close and 41 to open to exhaust. This permits the pressure on the left-hand side of the stop valve piston 143 to exhaust to the atmosphere through passage 144 and exhaust port 145. Pressure had previously forced the piston 143 to the right through the passages 146 and 144 thereby seating valve 86 on the right-hand side and unseating it on the left-hand side. By relieving the piston 143 of pressure on the left-hand side the Valve 86 will be moved to the left and pressure in the chamber can come down past said valve and enter the passage 147. The closing of value 41 and opening of valve 42 by the action of stop 37 against pawl 38 occurs only when the longest cut-off is desired, as, for instance, when starting the locomotive from a dead stop. The ratchet wheel 36 has then reached the limit of its clockwise rotation and its next movement must be counterclockwise or in a direction which will release pawl 38 and permit valve 41 to open and valve 42 to close. The purpose of the valves 41 and 42 is to admit or to exhaust air to the left of piston When starting the locomotive there is. of course, no back pressure until motion and exhaust actually begin so that the bellows dia phragm 106 will be moved to its extreme left hand position by the power of spring 107. At such times the lever 111 will be pushed upwardly and the valve 150 unseated, a condition which under ordinary operating circumstances would produce lengthening of the cut-off as described. But since the longest possible cut-off already exists under the conditions presumed no further lengthening is possible and in order to stop the device and prevent waste of air the valve 86 is seated in its righthand position by the action of the pressure on piston 143. But just as soon as the back pressure develops to the point for set shortening of the cutclockwise rotation of wheel 36. This immediately releases the pressure from behind piston 143, the exhaust taking place through valve 41. Then when the first lengthening motion is required valve 86 can freely unseat at the right and seat at the left so that exhaust of air through passages 147 and 148, which is necessary to such operation, can take place.

As long as arm 112 is moved upwardly and arm 111 downwardly, which is the condition supposed throughout the foregoing descrip tion and not the condition illustrated in Fig. 3, the pressure will pass down through the bleed port 148 to the underside of the diaphragm 149 causing said diaphragm to move upwardly since the area below it is greater than the area exposed to pressure above it. In this condition valve 150 is closed and communication between passage. 147 and the atvalve 113 to seat and diaphragm 91 will move the member 92 upwardly against its seat so that exhaust from passage 87 will be cut oft. This allows air in chamber 81 to build up to the same pressure to which chamber 80 is charged, and spring 155 which was compressed when valve was moved to the right,

now moves the said valve to central position,

bringing the entire controlling mechanism to rest.

If for any reason, the speed of the locomotive decreases, the hack pressure will also decrease and spring 107 will move arm 109 farther to the left, first taking up slight clearance between end of arm 111 and valve 150' and then raising said valve. Pressure below the diaphragm 149 will thereby he suddenly reduced, allowing member 152 to exhaust air from passage 147 through the exhaust ports 151. Due to the above, pressure which will be suddenly reduced in chamber 80, will permit the piston 79 to be moved to the left by the greater pressure in chamber 81. This motion is exactly the reverse of the motion which took place before.

As the slide valve 85 is carried to the left by the piston 79 pressure will initially enter the chamber 81 in order to keep up a good sup ply in this chamber and ensure a prompt movement-of the piston to the left. After this, pressure will be introduced to the passage 76 and then to the chamber'120 below the operating piston in the manner before indicated when the cut-off was being shortened and also to the passage 119 to the righthand end of the piston 133. The piston 133 will thereupon move to the left-and rock the guard 128 to the left raising the right-hand arm 129 and lowering the left-hand arm 130. As the operating piston 95 moves upwardly the ratchet 127 will engage the ratchet wheel 36 and the ratchet 126 will ride against the substantially vertical face 135 and thus be held away from the wheel 36. From this it will be seen that the wheel 36 will be rotated in a clockwise direction, that the pin 34 will be moved downwardly and with'it the cross head 30 which, acting upon the pin 27 in the slot 29 will move the operating rod 25 to the left. This actuates the valve operating lever 19 to move the valve in chest 12 of the power reverse gear to lengthen the cut-off;

Furthermore, the cut-off will be lengthened continuously step by step in gradually increasing amounts until such time as the back pressure once again assumes the predeterminedconstant value desired.

It is desired to point out that this constant back pressure does not vary extensively as might be assumed fr am this description. A differential of, for instance, one pound is permitted by the clearance allowed between the ends of arms 111 and 112 and the valves 113 and 150. For instance, if back pressure to be carried is ten pounds, the controller is set to shorten cut-off at ten and one-half pounds and lengthen it at nine and one-half pounds. Between these pressures valves 118 and 150 are both closed and device is at rest. The adjustment is a step by step operation which is continuous as long as back pressure is above or below setting of controlling member.

To sum up the operation of the apparatus without referring to the passages by number, it might be stated in the first place that our controller A taken as a whole is in effect a small engine operated by fluid pressure preferably air. After the reverse lever has been moved into one corner or the other and the throttle of the locomotive opened, air pres sure is brought to this controlling engine ready for utilization as soon the back pressure reaches the predetermined constant value. When this is exceeded or not reached certain valves are brought into play to cause the operating piston to move upwardly. The motion of the operating piston rotates the ratchet wheel 36 which moves the cross head 30 and the operating rod 25 either to the right or to the left as conditions may require. In forward motion of the locomotive, motion to the right of the operating rod 25 will cause the cut-ofi to shorten and motion to the left will cause it to lengthen. In reverse movement of the locomotive motion to the right will cause the cut-off to lengthen and motion to the left will cause it to shorten.

It will, therefore, be seen that in a device of this character we have provided an exceedingly simple and eflicient means for causing the apparatus to function either when maximum capacity is desired from the locomotive or when less than maximum capacity is desired. And the importance of this feature will be more clearly apparent when it is realized how often locomotives, operating in one direction and then returning, are subjected to an unbalanced condition of loading insofar as the load may or may not require the maximum power of the locomotive. For instance, ascending grades in one direction will be descending grades in the other; loaded cars in one dir ction may be empty cars on the return; shorter schedules in one direction will require higher running speeds than on the return; more stops in one direction than in the other but withthe same schedule time will require higher running speeds and trains that may run more cars in one direction than in the other will require different amounts of power from the same locomotive. Several combinations of the above conditions may be encountered in one direction and a difierent combination on the return.

The maximum capacity setting will be constant as will also the less than maximum and the less than maximum may be 7 5, 50, 25 or any desired percent of the maximum, the same to be determined by the requirements of operation in the less than capacity direction of the train or whenever less than maximum capacity is wanted.

We claim l. The method of operating a locomotivein which draft is created by exhaust steam, which consists 1 in adjusting the cut-off regardless of changes in speed so as to maintain substantially constant either that predetermined back pressure which will result in aximum capacity when such capacity is desired or that predetermined lower back pressure which will result in maximum economy when less than maximum capacity is desired.

In a locomotive, an apparatus for maintaining either one of two predetermined back pressures sul'rtantially constant, one for max imum capacity and the other for maximum eiiicien cy when less than maximum capacity is desired; said apparatus including in combination with the locomotive cylinders, pistons, valves, valve gear and exhaust; a power reverse gear, and a motor device for actuating said reverse gear having a member which is movable by changes in back pressure, means opposing and preventing said motion up to that predetermined back pressure which will produce maximum efiiciency when less than maximum capacity is desired, and means for applying fluid pressure to said movable memher to increase its effective opposition up to that predetermined back pressure which will result in maximum capacity, said motor device functioning to hook back the reverse gear when the back pressure rises above either of the two pressures for which the device may be set, and to advance it when the back pressure falls below said pressures.

3. In a steam locomotive having a boiler and an enginemans cab, the combination with the locomotive cylinders, pistons, valve gear, valves, power reverse gear and exhaust, of apparatus for maintaining either one of two predetermined back pressures substantially constant one for maximum capacity and the other for maximum efficiency when less than maximum capacity desired. said apparatus including a motor means for causing actuation of the power reverse gear having a member which is movable by changes in back pressure, means opposing and preventing said motion up to that predetermined back pressure which will produce maximum efliciency when less than maximum capacity is desired. and means in the cab with a connection to said motor means'for increasing the effective opposition of said urging means up to that predetermined back pressure which Will result in maximum capacity, said motor means functioning to hook back the reverse gear when the back pressure rises above either of the two pressures for which the device may be set and to advance it when the back pressure falls below said pressures.

In testimony whereof, we have hereunto signed our names.

ED vVIN S. PEARCE. RAYMOND W. RETTERER. EDMOND C. KARIBO. 

